Protective cooling system for thermionic apparatus



Dec. 19, 1933. H. J. NOLTE 1,940,319

PROTECTIVE COOLING SYSTEM FOR THERMIONIC APPARATUS Filed Dec. 24, 1928 JOU/iCf 0F F/LAME/VT ENERGY Inventor: Henry J. Nolte,

y ,LLZZQ His Attorney.

Patented Dec. '19, 1933 I STA ES A' EN fjQiiFj' F frRo'r acrrva' COOLING SYSTEM FOR I THERYMIONIGKAPPARATUS Henry J. None. Schenectady, N. assignorto General Electric Company, a corporation of L The present "invention relates to a power-tube New York Application December 24, 1928 I 1Serial-No. 328,198 1 s Claims.j(Cl. 250 275) 7 'equipmentymore particularly to a protective system *for'ensuring the application of a cooling fluid to the various heated parts of a thermionic device during operation.

a In the operation of transmitter tube apparatus,

it hasbeenforind that when the stem through which the-filamentleading-in I conductors nor .mally'pass, tendsto become heated fissures may condition is due, in" some measure, to the fact that the heat produced in these conductors by current flow is more or less confined by the cylindrical glass wall forming the reentrant stem. It is therefore necessary to provide a means for cooling the pinch seal and in the past it has "been customary to insert arubber tubing into the reentrant stem in such a manner that acooling fluid-may be directed against the leading-in conductors and the pinch seal. "tical matter, the detail of inserting the tubing is- 7 However, as'a pracsometimes neglected at the' time the filament 1 circuit isinitially'energized whereuponthe heat 'generatedby the large filament current causes the seal to become unduly hot.

-.Am'ong theobjects of the invention is to provide a means which will ensure the insertion of the tubing into the reentrant stem at the time the tube is operated, thereby to provide a positive protection of the stem against high temperature, and, in general, to assurethe maintenance of certain portions of the envelope, subject to considerable heat during operation, relatively cool.

filament circuit is affixed and which device is brought into operation only when the conduit is placed in such a position with respect to the thermionic apparatus that a cooling fluid is properly directed against the'heated parts.

For

a complete description of the invention, reference should be had to the accompanying drawing in which the figure is an elevational view of the tube and conduit.

In the drawing, numeral 1 designates the glass bushings receivethefllameht cables 5,:5! apertures are also formed in the cap, one of:

portion of an evacuated envelopathe lower end ;jof which terminates in a cylindrical anode 2 and the upperend-in a reentrant glassportionS. Within the anode there is mounted" in any suitable manner, a plurality of cooperating electrodes comprising a rectilinear-filamentary cathode. and a cylindricalgrid or electrostatic control member.

-The upper end of the filamentary cathode is sup portedfrom the reentrant stem 3 by'ineansof form in the pinch seal and 'the'vacuum fail. This ible cables '5, 5 carrying a plurality of terminals 6, 6. The grid is supported within the-anode-by meansof a grid clamp Lto which connection is made by a flexible strip lead 8 taken through the side of the envelope by means ofa'tubulation 9. In order to space the filament conductorsrigidly I from one another and to remove the'mechanical stress at the seal due to the lever effect of the conductors at this point,.there"is provided a. metallic cap 10 which fits 'over the upper end of the 175 envelope and is secured thereto in any suitable manner. The cap 10 contains a plurality ofisymmetrically'spaced apertures withinwhich bushings. 11 of insulated material are fitted; these Other 30 which may be utilized for the reception of a flexible rubber tubing 12 which, is employed for the purpose of directing acooling fiuid against the lower portions of the filament conductors, the 35 pinch seal and other heated parts, and others of which (not shown) may serve as a means of egress for the cooling fluid from the interior of the stem. The tubing 12 extends a considerable distance along the reentrant stem andis bent to such a shape and constituted of such length as will most effectively perform this purpose. 1 The upper end of the tubing 12 is carried through the aperture and terminates in a conical extension or bushing member 13, preferably. ofa 5, phenolic condensation product such as bakelite having a function which will be explained hereinafter. The fluid concluit'is continued through a nozzle 14 located in register with the bushing member and which, when in an operative position, may be seated on the said member. The nozzle 14 is carried by a piece of stiff tubing 15, preferably bakelite which is adapted at its free end to engage with a rubber air supply manifold 16. The tubing 15 is provided with a swivel joint '95 17 of any suitable design. A vane 18 is affixed rigidly to the swivel member, which vane is so positioned that when the nozzle 14 is firmly seated on the conical bushing 13, which position is indicated in dotted line, an electrical circuit is closed across the contacts 19, 19 thereby to establish a circuit through a relay 20 energized preferably from mains of commercial voltage. The energization of relay 20 causes a circuit to be completed through an armature 21 and a contact 22 so that current from a source of electromotive force 23 will flow through the filament. It will be evident that the apparatus and circuit arrangement described provide a positive means for interlocking the operation of applying the air or other cooling fluid to the tubing which directs the fluid toward the filament conductors and the pinch seal with the operation of energizing the filament. It is further apparent that if desired, the position of the vane member 18 on the swivel joint may be adjusted to give any desired time relation between these operations. While I have shown and described by way of example the relay 20 as controlling the filament circuit, it is obvious that if desired, control may be exercised on the grid, plate or any other convenient electrode within the thermionic device so that when any of these electrodes are energized, a supply of cooling fluid is assured to the tubing 12. In addition to the necessity of providing an interlocking arrangement such as dis closed herein. it has been found desirable to synchronize by suitable switches, the operation of supplying the high voltage to the plate circuit with that of starting up the air pump motor so as to eliminate the possibility of the operator failing to start the pump.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. The combination of thermionic apparatus and a cooling accessory, said apparatus including an envelope and a plurality of cooperating electrodes, said envelope terminating in a reentrant stem, a leading-in conductor for one of said electrodes, said conductor passing through the stem, means for directing a cooling fluid against the stem in the region of said conductor, said means comprising a stationary conduit mounted within the stem and a fluid-supply conduit which is movable into and out of engagement with said stationary conduit, a source of current connected to the leading-in conductor for energizing the said one electrode, and means for preventing energization of the said one electrode except when the fluid-supply conduit is moved into engagement with said stationary conduit.

2. The "combination of thermionic apparatus and a cooling accessory, said apparatus including an envelope and a plurality of cooperating electrodes, said envelope terminating in a reentrant stem, a leading-in conductor for one of said electrodes, said conductor passing through the stem, means for directing a cooling fluid against the stem in the region of said conductor, said means comprising a stationary conduit mounted within the stem and a fluid-supply conduit which is movable into and out of engagement with said stationary conduit, a source of current connected to the leading-in conductor for energizing the said one electrode, and means for preventing energization of the said one electrode except when the fluid-supply conduit is moved into engagement with said stationary conduit, said last-mentioned means comprising an electrical contact device mounted on the movable conduit.

3. The combination of thermionic apparatus and a cooling accessory, said apparatus comprising an envelope and a plurality of cooperating electrodes including a filament, said envelope terminating in a reentrant stem and provided with a cap, leading-in conductors for said filament, the conductors passing through the stem and cap, means for directing a cooling fluid against the stem in the region of said conductors, said meanscomprising a stationary conduit secured to said .cap and extending into said stem, a fluid supply HENRY J NOLTE. 

